Browse Topic: Braking systems
This article analyses the fundamental curving mechanics in the context of conditions of perfect steering off-flanging and on-flanging. Then conventional, radial, and asymmetric suspension bogie frame models are presented, and expressions of overall bending stiffness kb and overall shear stiffness ks of each model are derived to formulate the uniform equations of motion on a tangent and circular track. A 4 degree of freedom steady-state curving model is formulated, and performance indices such as stability, curving, and several parameters including angle of attack, tread wear index, and off-flanging performance are investigated for different bogie frame configurations. The compatibility between stability and curving is analyzed concerning those configurations and compared. The critical parameters influencing hunting stability and curving ability are evaluated, and a trade-off between them is analyzed. For the verification, the damped natural frequencies and mean square acceleration
As a distributed wire control brake system, the electro-mechanical brake (EMB) may face challenges due to the need to integrate the actuator in the limited space beside the wheel. During extended downhill braking, especially on wet roads with reduced adhesion, the EMB must operate at high intensity. The significant heat generated by friction can lead to thermal deformation of components, such as the lead screw, compromising braking stability. This paper focuses on pure electric light trucks and proposes a tandem composite braking method. This approach uses an eddy current retarder (ECR) or motor to provide basic braking torque, while the EMB supplies the dynamic portion of the braking torque, thereby alleviating the braking pressure on the EMB. First, a driver model, tire model, motor model, and braking models are developed based on the vehicle's longitudinal dynamics. In addition, the impact of various factors, such as rainfall intensity, road slope, ramp length and vehicle speed, on
Hybrid vehicles are driven by the vehicle controller, engine controller and motor controller through torque control, and there may be unexpected acceleration or deceleration of the vehicle beyond the driver's expectation due to systematic failure and random hardware failure. Based on the torque control strategy of hybrid vehicles, the safety monitoring model design of torque control is carried out according to the ISO 26262 safety analysis method. Through the establishment of safety goals and the analysis of safety concepts, this paper conducts designs including the driver allowable torque design for safety monitoring, the driver torque prediction design for safety monitoring, the rationality judgment design of driver torque for safety monitoring, the functional safety degradation design, and the engine start-stop status monitoring, enabling the system to transition to a safe state when errors occur. Firstly, the design of the driver's allowable torque includes the allowable requested
Vehicle sideslip is a valuable measurement for ground vehicles in both passenger vehicle and racing contexts. At relevant speeds, the total vehicle sideslip, beta, can help drivers and engineers know how close to the limits of yaw stability a vehicle is during the driving maneuver. For production vehicles or racing contexts, this measurement can trigger Electronic Stability Control (ESC). For racing contexts, the method can be used for driver training to compare driver techniques and vehicle cornering performance. In a fleet context with Connected and Autonomous Vehicles (CAVS) any vehicle telemetry reporting large vehicle sideslip can indicate an emergency scenario. Traditionally, sideslip estimation methods involve expensive and complex sensors, often including precise inertial measurement units (IMUs) and dead reckoning, plus complicated sensor fusion techniques. Standard GPS measurements can provide Course Over Ground (COG) with quite high accuracy and, surprisingly, the most
Due to the frequent and significant changes of the motor torque of hybrid vehicles during driving often occurring with the driving conditions, and the existence of the transmission tooth surface switching caused by the change in torque direction, as well as the underdamping characteristics caused by the relatively simple transmission system, the vehicle is prone to vehicle body shaking problems under conditions such as the transformation from acceleration conditions to energy recovery conditions, and exit from energy recovery. In order to ensure the ride smoothness of the hybrid vehicle while improving its power response performance, aiming at the underdamping characteristics of its transmission system, this paper develops a transmission PCM vibration suppression control strategy based on the vehicle control system to enhance the torque response and smoothness after Tip out or Tip in after braking. This strategy includes the identification of preconditions and the active intervention
Following the current need of the automotive sector on reducing secondary emissions coming from non-exhaust sources, this paper presents an innovative zero-emissions magneto-rheological braking system, specifically designed to reach future brake emission targets while maintaining safety brake performance. In particular, the article focusses on the experimental setup design to evaluate a full-sized brake prototype under real load conditions and it presents the first experimental results. The zero-emission braking prototype has been developed for reaching performance compatible with the automotive application, specifically a segment-A vehicle, being able to generate enough braking torque as to perform an emergency brake maneuver without any other traditional braking system. A central aspect to confirm the system’s performance is the development of a test bench engineered for assessing the magneto-rheological braking technology. Detailed insights into the comprehensive strategy
The braking performance of newer anti-lock braking system (ABS) equipped vehicles on roads with varying wetness levels is not well studied. Two late-model ABS-equipped vehicles were used to perform ABS-engaged braking tests on dry and wet asphalt and concrete surfaces from which vehicle speed and deceleration as a function of time were calculated. Tests were initially conducted on a dry surface before a water truck distributed water onto the road to create a wet road condition. A continuous series of tests were then performed until the road dried and the cycle was repeated multiple times. Across all tests of both vehicles on both road surfaces, deceleration levels generally decreased when the road was wet and returned to dry levels only when less than 25% of the road surface remained wet. Also, wet deceleration levels were high compared to the historical values used for wet roads. These findings provide a useful and readily identifiable boundary between what can be considered a dry and
The Electro-Mechanical Brake (EMB) eliminates the traditional hydraulic pipeline arrangement through high-performance servo motor at the vehicles brake calipers. This provides a foundation for intelligent electric vehicles to achieve high-precision, fast response, and strong robustness in brake clamping force control. However, EMB faces some tricky nonlinear disturbances such as varying system stiffness disturbances, complex friction obstruction, etc., which leads to a decline in clamping force control performance. Therefore, this paper proposes a high-quality clamping force control for EMB considering nonlinear disturbances. First, we establish an EMB actuator model including the permanent magnet synchronous motor, mechanical transmission mechanism, and system stiffness characteristics. Next, the high-quality clamping force control strategy for EMB is designed. An outer-loop clamping force regulator is developed using Proportional-Integral-Derivative (PID) feedback control and
The research object of this project is the anti-slip and lateral stability control technique for a distributed three-axis drive vehicle. What differs from the traditional four-motor power system layout is that the third axle has two motors, while the second axle only has one motor. Compared with the traditional design, this layout can reduce dependence on battery performance and maintain motor operation in a high-efficiency range by switching between different operating modes. For example, when driving at high speeds, only the motor on the second axle works, which can improve motor efficiency. When accelerating or climbing, all motors work to provide a large power output. In the research, the vehicle model was first established in Simulink, and then co-simulated with TruckSim. The drive anti-slip control first identified the optimal slip rate for the road, and then used the sliding mode control to determine the driving torque for each wheel, achieving good control effects under various
Onboard sensing and Vehicle-to-Everything (V2X) connectivity enhance a vehicle's situational awareness beyond direct line-of-sight scenarios. A team led by Southwest Research Institute (SwRI) demonstrated 20% energy savings by leveraging these information streams on a 2017 Prius Prime as part of the first phase of the ARPA-E-funded NEXTCAR program. Combining this technology with automation can improve vehicle safety and enhance energy efficiency further. In the second phase, SwRI demonstrated 30% energy savings over the baseline. This paper summarizes the efforts to achieve 30% savings on a 2021 Honda Clarity PHEV. The vehicle was outfitted with the SwRI Ranger automated driving suite for perception and localization. Model-based control schemes with selective interrupt and control (SIC) were used to override stock vehicle controls and actuate the accelerator, brake, and electric power steering system, enabling drive-by-wire and steer-by-wire functionalities. Key algorithms contributing
The unicycle self-balancing mobility system offers superior maneuverability and flexibility due to its unique single-wheel grounding feature, which allows it to autonomously perform exploration and delivery tasks in narrow and rough terrains. In this paper, a unicycle self-balancing robot traveling on the lunar terrain is proposed for autonomous exploration on the lunar surface. First, a multi-body dynamics model of the robot is derived based on quasi-Hamilton equations. A three-dimensional terramechancis model is used to describe the interaction between the robot wheels and the lunar soil. To achieve stable control of the robot's attitude, series PID controllers are used for pitch and roll attitude self-balancing control as well as velocity control. The whole robot model and control strategy were built in MATLAB and the robot's traveling stability was analyzed on the lunar terrain.
Since the introduction of ABS (1978), TCS (1986) and ESC (1995) in series production, the number of modern vehicle dynamics control functions and advanced driver assistance systems (ADAS) has been continuously increasing. Meanwhile, many functions are available that influence vehicle motion (vehicle dynamics). Since these are only partially and not hierarchically coordinated, the control of vehicle motion is still suboptimal. Current megatrends (automated driving, electromobility, software-defined vehicles) and new key technologies (steer-by-wire, brake-by-wire, domain-based E/E architectures) lead to an increasing number of electrified, motion-relevant components being introduced into series production. These components enable the development of an integrated chassis control (ICC) that controls all motion-relevant components, networks them with each other and coordinates them holistically to optimally control the vehicle motion regarding an adjustable desired driving behavior. Vehicle
Tractor-semitrailers play an important role in the transportation industry. However, global warming and the rapid advancement of energy technologies have driven the transformation of high-emission vehicles, such as tractor-semitrailers, to be powered by new energy sources in order to achieve goals related to energy conservation, emission reduction, and cost savings. By using the motor as the primary driving force, the energy recovered during braking or coasting can be converted into electricity and stored in the battery for later use. While much research has been conducted on braking control and energy recovery for passenger cars, there is limited research on tractor-semitrailers. Additionally, the jackknife is a critical factor to consider under high-speed conditions. To investigate the braking energy recovery of electric tractor-semitrailers, tire and motor models were developed based on the turning and braking conditions of such vehicles. Taking into account the load transfer effect
This study presents a control co-design method that utilizes a bi-level optimization framework for parallel electric-hydraulic hybrid powertrains, specifically targeting heavy-duty vehicles like class 8 semi-trailer trucks. The primary objective is to minimize battery energy consumption, particularly under high torque demand at low speed, thereby extending both battery lifespan and vehicle driving range. The proposed method formulates a bi-level optimization problem to ensure global optimality in hydraulic energy storage sizing and the development of a high-level energy management strategy. Two nested loops are used: the outer loop applies a Genetic Algorithm (GA) to optimize key design parameters such as accumulator volume and pre-charged pressure, while the inner loop leverages Dynamic Programming (DP) to optimize the energy control strategy in an open-loop format without predefined structural constraints. Both loops use a single objective function, i.e. battery energy consumption
In hybrid electric vehicles (HEVs), optimizing energy management and reducing system losses are critical for enhancing overall efficiency and performance. This paper presents a novel control strategy for the boost converter in hybrid electric vehicles (HEVs), aimed at minimizing energy losses and optimizing performance by modulating to a higher boost converter voltage only when necessary. Traditional approaches to boost converter control often lead to unnecessary energy consumption by maintaining higher voltage levels even when not required. In contrast, the proposed strategy dynamically adjusts the converter's operation based on real-time vehicle demands, such as driver input, Engine Start-Stop (ESS) events, Active Electric Motor Damping (AEMD), entry and exit transitions for Engine Fuel Cut-Off (DFCO), Noise-Vibration-Harshness (NVH) events like lash-zone crossing and other specific operational conditions. The control strategy leverages predictive algorithms and real-time monitoring
To address the challenges of complex operational simulation for Electric Vehicles (EVs) caused by spatial-temporal variations and driver behavior heterogeneity, this study introduces a dynamic operation simulation model that integrates both data-driven and physics-based principles, referred to as the Electric Vehicle-Dynamic Operation Simulation (EV-DOS) model. The physics-based component encompasses critical aspects such as the powertrain energy transfer module, heat transfer module, charge/discharge module, and battery state estimation module. The data-driven component derives key features and labels from second-by-second real-world vehicle driving status data and incorporates a Long Short-Term Memory (LSTM) network to develop a State-of-Health (SOH) prediction model for the EV power pack. This model framework combines the interpretability of physical modeling with the rapid simulation capabilities of data-driven techniques under dynamic operating conditions. Finally, this study
Gray cast iron is a cost-effective engineering material widely used for heavy duty engine blocks and brake rotor discs in vehicles. Thermomechanical fatigue (TMF) frequently occurs during vehicle operation due to temperature fluctuations in brake rotors. To speed up the design of the component, design structurally sounding brake rotors, and prevent premature thermally induced cracking, it is critical to investigate TMF behavior of the gray cast iron. This study presents a series of fatigue tests, including isothermal low cycle fatigue (LCF) tests at temperatures up to 700°C, as well as in-phase (IP) and out-of-phase (OP) TMF tests across various temperature ranges. Because of the asymmetric behavior in tension and compression, creep behaviors in both tension and compression and oxidation are also studied. These behaviors are the key to enable simulation of thermally induced cracks in rotors.
As a crucial component of highway freight systems, tractor semitrailer vehicles play a key role in the transportation industry. However, their complex vehicle structure can lead to significant lateral instability during emergency obstacle avoidance, posing challenges to the vehicle's dynamic stability and safety. To enhance the emergency obstacle avoidance lateral stability of tractor semitrailer vehicles, a direct yaw moment lateral stability control strategy based on differential driving/braking is proposed. First, a 3-degree-of-freedom ideal linear dynamic model of the tractor-semitrailer is established, and its accuracy is validated. Then, a lateral stability control strategy for emergency obstacle avoidance is proposed. The upper-layer controller employs an improved feedforward differential model-free adaptive control (IMFAC) method to track the target yaw rate and vehicle sideslip angle, while the lower-layer controller focuses on optimizing tire load rate. Additionally, a drive
The improvement of heat dissipation performance of ventilated brake discs is vital to braking safety. Usually, the technical approaches shall be material optimization or structural improvement. In this paper, a simulation model of the heat transfer of brake discs is established using STAR-CCM+ software. Cast iron, aluminum metal matrix composite (Al-MMC), and carbon-ceramic composite materials (C-SiC) are compared. The results show that: Al-MMC has better thermal conductivity so that a more uniform temperature gradient distribution shall be formed; C-SiC has poorer heat capacity yet, according to previous studies, it has better thermal stability, which is the ability to ensure its friction factor under high-temperature condition; cast iron performs better with convective heat transfer rate, which enhances the heat transfer between the surface and surrounding flow field. Based on the results, this paper proposes four types of material combined brake discs using different friction
When the aircraft towbarless towing vehicle (TLTV) drives on road surfaces that are wet, icy, oily, or covered with debris, as well as under conditions such as overloaded towing, uneven distribution of aircraft weight, sudden acceleration and sharp turns, brake system failures, or severe tire wear, it may slip due to a mismatch between traction force and ground adhesion. As a key piece of ground support equipment at airports, the anti-slip performance of TLTV is crucial for ensuring safe and efficient ground movement of aircraft. With continuous advancements in control technology, extensive research has been conducted on anti-slip control strategies for TLTV. This paper reviews relevant literature in the field of anti-slip control for TLTV in recent years, focusing on the current status of anti-slip control technology development, control strategies, and the application of co-simulation technology in anti-slip control. Based on co-simulation using Matlab and Adams software, this paper
Clamping force control in Electromechanical Brake (EMB) systems must overcome various nonlinear characteristics, such as motor distorted voltage, Back Electromotive Force (EMF), and actuator friction disturbances. Therefore, modeling and parameter identification of these nonlinearities are necessary. This paper first proposes a motor parameter identification method based on the mathematical model of a Permanent Magnet Synchronous Motor (PMSM). A combination of the Least Square Method and Particle Swarm Optimization (PSO) is used to stepwise identify both the electrical and mechanical parameters of the motor. The accuracy of the identified parameters is validated by comparing simulation results with test bench responses. The identified parameters are applied to design the motor Back EMF compensation module, the distorted voltage compensation module, and to tune the current loop parameters. Next, a lumped parameter friction model suitable for closed-loop clamping force control in EMB
This paper introduces an innovative in-wheel electric drive system designed for all-wheel drive Formula Student Electric racing cars. The system utilized AMK's DD5-14-10-POW-18600-B5 model as the driving motor, with a gearbox transmission ratio of 13.2 determined through Optimum Lap simulation. A two-stage gear reducer was integrated into a unified hub-spoke assembly, which connected directly to the ten-inch carbon fiber rim. In this paper, three conventional FSEC planetary gear reducer shafting designs are introduced, and a new shafting structure is proposed. Then the four structures are compared in multiple dimensions. Subsequently, we designed the shafting of the gear group, determined the size parameters of the shafting structure and the bearing type, and completed the verification. The planetary carriers were integrated with the wheel-edge suspension columns. Meanwhile, a special floating brake disc mounting method was employed, which increased the brake disc's heat capacity by
The use of drum brakes in Battery Electric Vehicles (BEVs) offers numerous benefits, including energy efficiency, reduced brake dust emissions, and reliable performance under challenging weather conditions. The capability of regenerative braking reduces the friction brake application frequency in BEVs and therefore the brakes can be prone to corrosion and performance degradation especially considering conventional disc brake systems. The closed design of a drum brake prevents corrosion of the friction-components by sealing out water, dirt or snow. A common sealing concept is performed with a labyrinth between the gap of the rotating drum and the axle mounted backplate. A hermetical isolation of water and snow ingress into the drum cannot be achieved with this concept, so additional aerodynamic measures are necessary to deflect the air/water path and protect the inner brake components. Additionally, interfaces like wheel cylinders, electric park brake parts, brake shoe pins, and axle
Traction control plays a key role in improving vehicle safety, especially for driving scenarios involving low levels of tire-road friction. Over the past 30 years, academic and industrial research in traction controllers has mainly favored deterministic approaches. This paper introduces a traction control strategy based on a deep reinforcement learning agent tailored for straight-line acceleration maneuvers from standstill in low-friction conditions. The proposed agent is trained on two different electric vehicles, a front-wheel drive city car (from EU vehicle segment A), and a rear-wheel drive sedan (from EU vehicle segment D). The paper presents a deep reinforcement learning agent formulation suitable for training on different vehicles, assesses the performance of the resulting controllers in comparison with a benchmarking integral sliding mode controller, and evaluates their response to changes in vehicle mass, powertrain parameters and tire-road friction conditions. The assessment
This paper presents a novel Dual-source Electro-Hydraulic Brake system (D-EHB) that incorporates a redundant braking module to enhance safety and reliability. The D-EHB is designed to address the critical issue of brake failure in vehicles, which can lead to severe accidents. The D-EHB system comprises two independent units: the Main Brake Unit (MBU) and the Redundant Brake Unit (RBU). Each unit has its own hydraulic power source. The MBU's hydraulic pressure is generated by a combination of a servo motor, ball screw, and servo piston, while the RBU has a simpler structure, with hydraulic pressure generated by a motor and plunger pump combination. Mathematical models for each component of the D-EHB have been developed and validated using AMESim. The mathematical models of each part were then combined to design a wheel cylinder hydraulic pressure estimation algorithm that can calculate the wheel cylinder pressure based on motor and valve output signals, making the system applicable to
Brake-by-wire systems have received more and more attention in the recent years, but a close look on the available systems shows, that they have not reached full by-wire level yet. Most systems are still using hydraulic connections between main cylinder and the brake calipers on at least one axle to ensure functional safety. Mostly, this is the front axle, since the front brakes have to convert more kinetic energy during braking manoeuvers. Electromechanical actuators are currently used for rear brakes in hybrid brake-by-wire applications solely, since a loss of the front brake calipers can lead to severe conditions and control loss of the vehicle during braking. Further, the higher mass of battery electric vehicles (BEVs) leads to much higher braking forces on both axles and to increased sizes of the electromechanical calipers. This article presents a concept for a brake-by-wire system for battery electric vehicles, which features electromechanical brake actuators on all corners and a
With the development of automotive electrification and intelligent technology, vehicles have higher and higher requirements for braking systems. On the one hand, it requires it to have an active braking function, and at the same time facilitates the integration with other control systems of the chassis domain. The system should minimize oil pollution as much as possible, and under the premise of ensuring the pedal force, it can be used to recover the brake energy as much as possible to improve the range of electric vehicles as possible. The new brake system based on Electronic mechanical brake (EMB) as a line -controlled decoupling braking system can not only meet the needs of the brake pedal sensation, but also achieve continuous and accurate control of braking power. It can effectively Taking into account braking economy, braking safety, and braking comfort. In addition, the development of EMB technology is still immature and the failure rate is high, so research on EMB's fault
Videos from cameras onboard a moving vehicle are increasingly available to collision reconstructionists. The goal of this study was to evaluate the accuracy of speeds, decelerations, and brake onset times calculated from onboard dash cameras (“dashcams”) using a match-moving technique. We equipped a single test vehicle with 5 commercially available dashcams, a 5th wheel, and a brake pedal switch to synchronize the cameras and 5th wheel. The 5th wheel data served as the reference for the vehicle kinematics. We conducted 9 tests involving a constant-speed approach (mean ± standard deviation = 57.6 ± 2.0 km/h) followed by hard braking (0.989 g ± 0.021 g). For each camera and brake test, we extracted the video and calculated the camera’s position in each frame using SynthEyes, a 3D motion tracking and video analysis program. Scale and location for the analyses were based on a 3D laser scan of the test site. From each camera’s position data, we calculated its speed before braking and its
Drivers sometimes operate the accelerator pedal instead of the brake pedal due to driver error, which can potentially result in serious accidents. To address this, the Acceleration Control for Pedal Error (ACPE) system has been developed. This system detects such errors and controls vehicle acceleration to prevent these incidents. The United Nations is already considering regulations for this technology. This ACPE system is designed to operate at low speeds, from vehicle standstill to creep driving. However, if the system can detect errors based on the driver's operation of the accelerator pedal at various driving speeds, the system will be even more effective in terms of safety. The activation threshold of ACPE is designed to detect operational errors, and it is necessary to prevent the system from being activated during operational operations other than operational errors, i.e., false activation. This study focuses on the pedal operation characteristics of pedal stroke speed and
The Distributed Drive Electric Vehicles (DDEVs) offer advantages such as independently controllable driving and braking forces at each wheel, rapid response, and precise control. These features enable effective electronic stability control (ESC) by appropriately distributing torque across each wheel. However, traditional ESC systems typically employ single-wheel hydraulic differential braking, failing to fully utilize the independent torque control capabilities of DDEVs. This study proposes a hierarchical control strategy for distributed driving and braking ESC based on particle filter (PF) and fuzzy integral sliding mode control (FISMC). First, the vehicle state estimation layer uses a three-degree-of-freedom vehicle model and the PF to estimate sideslip angle and vehicle speed. Next, the target torque decision layer includes a target speed tracking controller and a yaw moment decision controller. The yaw moment decision controller uses the FISMC to determine additional yaw moment by
To further optimize the automatic emergency braking for pedestrian (AEB-P) control algorithm, this study proposes an AEB-P hierarchical control strategy considering road adhesion coefficient. First, the extended Kalman filter is used to estimate the road adhesion coefficient, and the recursive least square method is used to predict the pedestrian trajectory. Then, a safety distance model considering the influence factor of road adhesion coefficient is proposed to adapt to different road conditions. Finally, the desired deceleration is converted into the desired pressure and desired current to the requirements of the electric power-assisted braking system. The strategy is verified through the hardware-in-the-loop (HIL) platform; the simulation results show that the control algorithm proposed in this article can effectively avoid collision in typical scenarios, the safe distance of parking is between 0.61 m and 2.34 m, and the stop speed is in the range of 1.85 km/h–27.64 km/h.
This recommended practice covers the attachment of bonded anti-noise brake pad shims only. Mechanically attached shims (those without bonding) are not covered by this procedure.
From humble Chevrolet Bolts to six-figure Lucid Airs, every EV can reverse its electric motors to slow the vehicle while harvesting energy for the battery, the efficient tag-team process known as regenerative braking. Today's EVs do this so well that traditional friction brakes, which clamp onto a spinning wheel rotor or drum, can seem an afterthought. Witness Volkswagen's decision to equip its ID.4 with old-fashioned rear drum brakes, with VW claiming drums reduce EV rolling resistance and offer superior performance after long periods of disuse.
With current and future regulations continuing to drive reductions in carbon dioxide equivalent (CO2e) emissions in the on-road industry, the off-road industry is also likely to be regulated for fuel and CO2e savings. This work focuses on converting a heavy-duty off-road material handler from a conventional diesel powertrain to a plug-in series hybrid, achieving a 49% fuel reduction and 29% CO2e reduction via simulation. Control strategies were refined for energy savings, including a regenerative braking strategy to increase regenerative braking and a load-following hydraulic strategy to decrease electrical energy consumption. The load-following hydraulic control shuts off the hydraulic electric machine when it is not needed—an approach not previously seen in a load-sensing, pressure-compensated system. These strategies achieved a 24.1% fuel savings, resulting in total savings of 61% in fuel and 41% in CO2e in the plug-in series compared to the conventional machine. Beyond control
The sound generated by electric propulsion systems differs compared to the prevalent sound generated by combustion engines. By exposing listeners to various sound situations, the manufacturer can start understanding which direction to take to achieve compelling battery electric vehicle trucks from a sound perspective. The main objective of this study is to understand what underlying aspects decide the experience and perception of heavy vehicle–related sounds in the context of electrified propulsion. Using a thematic analysis of data collected at a listening experiment conducted in 2020, factors affecting the perception of novel sounds generated by a first-generation electric truck are investigated. A hypothesis is that the experience of driving or being a passenger in electric trucks will affect the rating and response differently compared to listeners not yet experienced with this sound. The results show that the combination of individual preference and experience, hearing function
Path-tracking control occupies a critical role within autonomous driving systems, directly reflecting vehicle motion and impacting both safety and user experience. However, the ever-changing vehicle states, road conditions, and delay characteristics of control systems present new challenges to the path tracking of autonomous vehicles, thereby limiting further enhancements in performance. This article introduces a path-tracking controller, time-varying gain-scheduled path-tracking controller with delay compensation (TGDC), which utilizes a linear parameter-varying system and optimal control theory to account for time-varying vehicle states, road conditions, and steering control system delays. Subsequently, a polytopic-based path-tracking model is applied to design the control law, reducing the computational complexity of TGDC. To evaluate the effectiveness and real-time capability of TGDC, it was tested under a series of complex conditions using a hardware-in-the-loop platform. The
Disc brakes play a vital role in automotive braking systems, offering a dependable and effective means of decelerating or halting a vehicle. The disc brake assembly functions by converting the vehicle's kinetic energy into thermal energy through friction. The performances of the brake assembly and user experience are significantly impacted by squeal noise and wear behaviour. This paper delves into the fundamental mechanisms behind squeal noise and assesses the wear performance of the disc brake assembly. Functionally graded materials (FGMs) are an innovative type of composite material, characterized by gradual variations in composition and structure throughout their volume, leading to changes in properties such as mechanical strength, thermal conductivity, and corrosion resistance. FGMs have emerged as a groundbreaking solution in the design and manufacturing of brake rotors, addressing significant challenges related to thermal stress, wear resistance, and overall performance. These
As wire control systems advance, they have given rise to a diverse suite of advanced driver assistance services and sophisticated fusion control capabilities. This article presents an innovative strategy for achieving comfortable braking in electric vehicles, propelled by the unwavering goal of enhancing driving experience. By integrating active suspension systems with brake-by-wire technology, the approach ensures that drivers retain their confidence throughout the braking process. The brake-by-wire system adeptly discerns the driver’s braking intent through the pedal’s displacement sensor. Utilizing this technology, we have developed a pioneering function aimed at delivering comfort braking control (CBC). This function not only refines the braking experience but also solidifies the driver’s trust in the braking system. Designed to counteract the head nodding effect during vehicle deceleration, the CBC system minimizes or even eradicates the jarring sensation of pitching for both the
The braking system is an essential element for ensuring the safe operation of vehicles. This research investigates the influence of electronic mechanical brakes on the control performance of permanent magnet synchronous motors, with a particular focus on variations in the load torque and inertial load. This study addresses challenges such as delayed responses in the clamping force and diminished control accuracy. To mitigate these issues, a Luenberger load torque observer is utilized for the real-time identification of load torque. The identified load torque is subsequently converted into a compensation current, which is integrated into the current loop as a feed-forward compensation signal to enhance the control performance. Additionally, to reduce the impact of variations in inertial load on the overall control system, this study employs a model reference adaptive algorithm for the online identification of rotational inertia, with the identification results being fed back to the load
Verifying training datasets in vision-based vehicle safety applications is crucial to understanding the potential limitations of detection capabilities that may result in a higher safety risk. Vision-based pedestrian safety applications with crash avoidance technologies rely on prompt detection to avoid a crash. This research aims to develop a verification process for vulnerable road user safety applications with vision-based detection functionalities. It consists of reviewing the application’s safety requirements, identifying the target objects of detection in the operational design domain and pre-crash scenarios, and evaluating the safety risks qualitatively by examining the training dataset based on the results of pre-crash scenarios classification. As a demonstration, the process is implemented using open-source pedestrian tracking software, and the pre-crash scenarios are classified based on the trajectories of pedestrians in an example training dataset used in a pedestrian
This work pioneers the development of eco-friendly brake pads using coconut fiber and sawdust as reinforcement materials, combined with abrasives and friction modifiers. The innovation lies in the utilization of these natural fibers, which are not only cost-effective and abundantly available but also contribute to the sustainability of brake pad manufacturing. The study aims to explore the feasibility and performance of these organic fibers in brake pad applications. Coconut fiber and sawdust were chosen for their unique properties, such as high strength-to-weight ratio and thermal stability, making them ideal candidates for enhancing brake pad performance. The inclusion of abrasives and friction modifiers further optimizes the braking efficiency and durability of the pads. Comprehensive testing was conducted, including hardness, compression, wear (using a pin-on-disc apparatus), and thermogravimetric analysis (TGA), to thoroughly evaluate the mechanical properties and thermal
The SAE Formula prototypes are developed by students, where in the competition, various aspects of project definitions are evaluated. Among the factors evaluated for scoring is the braking system, in which the present work aims to present the development and design of the braking system of a vehicle, prototype of Formula SAE student competition. As it is a project manufactured mostly by students, where the chassis, suspension system, electrical, transmission and powertrain are developed, it is important to first pass the static and safety tests, where the brakes of the four wheels are tested during deceleration at a certain distance from the track. To enable such approval and also to demonstrate, for the competition judges, the veracity of the system’s sizing, all the parameters and assumptions of the choice of the vehicle’s braking system are presented, thus ensuring their reliability, efficiency and safety. Using drawing and simulation software such as SolidWorks and Excel for
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